In recent years, attention has been focused on an optical image measurement technique of forming an image showing the surface morphology or internal morphology of a measurement object by using a light beam emitted from a laser light source or the like. Because this optical image measurement technique does not have invasiveness to human bodies unlike an X-ray CT device, it is expected to employ this technique particularly in the medical field.
Patent Document 1 discloses an optical image measurement device configured in a manner that: a measuring arm scans an object by using a rotary deflection mirror (Galvano mirror); a reference mirror is disposed to a reference arm; at the outlet thereof, such an interferometer is used that the intensity of a light caused by interference of light fluxes from the measuring arm and the reference arm is analyzed by a spectrometer; and the reference arm is provided with a device gradually changing the light flux phase of the reference light in non-continuous values.
The optical image measurement device disclosed in Patent Document 1 uses a method of so-called “Fourier Domain OCT (Optical Coherence Tomography).” That is to say, the morphology of the measurement object in the depth direction (z-direction) is imaged by applying a beam of a low-coherence light to a measurement object, obtaining the spectrum intensity distribution of the reflected light, and subjecting the obtained distribution to Fourier transform.
Furthermore, the optical image measurement device described in Patent Document 1 is provided with a Galvano mirror scanning with a light beam (a signal light), thereby being capable of forming an image of a desired measurement region of a measurement object.
Because this optical image measurement device scans with the light beam only in one direction (x-direction) orthogonal to the z-direction, a formed image is a 2-dimensional tomographic image in the depth direction (z-direction) along the scanning direction of the light beam (the x-direction).
Further, Patent Document 2 discloses a technique of scanning with a signal light in both the horizontal and vertical directions to thereby form a plurality of 2-dimensional tomographic images in the horizontal direction and, based on the plurality of tomographic images, acquiring and imaging 3-dimensional tomographic information of a measurement range. A method for 3-dimensional imaging is, for example, a method of arranging and displaying a plurality of tomographic images in the vertical direction (referred to as stack data or the like), and a method of forming a 3-dimensional image by subjecting a plurality of tomographic images to a rendering process.
Further, Patent Document 3 discloses a configuration of using such an optical image measurement device in the ophthalmic field.    [Patent Document 1] Japanese Unexamined Patent Publication No. 11-325849    [Patent Document 2] Japanese Unexamined Patent Publication No. 2002-139421    [Patent Document 3] Japanese Unexamined Patent Publication No. 2003-543